Ureaplasma urealyticum has been the agent most commonly linked with chorioamnionitis and low birth weight infants. Its association with chorioamnionitis is undeniable; the role of U. urealyticum in prematurity with or without IUGR remains controversial. From recent studies, it is obvious that only a subpopulation of individuals with cervicovaginal infection develop amniotic infections. Thus it is not surprising that controversy still exists concerning the role of infection in prematurity and IUGR. All studies to date have strictly compared isolation rates from the lower genital tract of different patient populations or have compared isolation rates from fetal membranes without regard to the incidence of maternal cervicovaginal infection, status of labor, or membrane rupture. This study will determine the association of intra-amniotic ureaplasmal infection with IUGR. Amniotic fluid and placenta will be quantitatively cultured for U. urealyticum at the time of cesarean section in women whose membranes are intact. Because U. urealyticum in the lower genital tract is often associated with other important genital pathogens that may also be lined with IUGR, all amniotic fluids and placentas collected at cesarean section will also be cultured for: Mycoplasma hominis, Mycoplasma genitalium, Chlamydia trachomatis, Trichomonas vaginalis, fungi, and anaerobic and aerobic bacteria. Cultural results will be correlated with the presence of inflammation in the placenta, the presence of polymorphonuclear leukocytes in the amniotic fluid, with noninfectious confounders associated with IUGR, and with aspects of pregnancy outcome other than IUGR, especially prematurity, morbidity, and mortality of the offspring. Particular attention will be given to the duration of labor prior to culture.